We present a systematic analysis of the four known large X-ray
flares detected to date on the eclipsing binary system Algol, using an
approach based on hydrodynamic simulations of decaying flaring loops
including sustained heating. This method yields, for the large
BeppoSAX Algol flare of Aug. 1997 (where a geometrical estimate of the
size of the flaring region is available) a more reliable size than
approaches based on the free decay of the flaring loop. For the three
flares analyzed here (one observed by EXOSAT, one by GINGA and one by
ROSAT) we show that indeed sustained heating is present in all cases,
so that the size of the flaring region is always smaller than
previously derived. No evidence for the very long loops previously
found through quasi-static analysis methods (extending out to several
stellar radii) is found. Instead, the flaring corona of Algol is found
to be rather compact. By comparing the imaging VLBI observations of
the radio corona of Algol with the recent location of the Algol flare
seen by BeppoSAX and with with present results, a consistent model of
the Algol corona is deduced: the corona is essentially concentrated
onto the polar regions of the K star in Algol, with a more compact
(smaller than the star) flaring component and a perhaps somewhat more
extended (comparable in size to the star) quiescent corona.